Toddbrook Reservoir damaged - Whaley Bridge evacuated

[sprinterguy]

I initially shared this in the Flooding Disruption thread, as Northern Rail services have now been suspended between New Mills and Buxton in response to this incident, but as the story continues to unfold and it has much wider ramifications for the local community and those affected, I thought it deserved it's own thread.

Due to the heavy rain over the past couple of days, part of the concrete spillway of Toddbrook Reservoir overlooking Whaley Bridge in Derbyshire has fallen away, and the village is being evacuated after the Environment Agency issued a 'danger to life' flood warning. Local residents are being advised to take essential supplies for "a number of days".

The Manchester Evening News article is being updated as events unfold.
https://www.manchestereveningnews.c.../reservoir-sealed-police-people-told-16681771

Whaley Bridge evacuated as 'danger to life' warning issued over fears dam could burst - live updates

The town is being evacuated after the Environment Agency issued a severe flood warning on Thursday lunchtime

TODDBROOK RESERVOIR OVERFLOWS AFTER 'CRUMBLING' IN FLOODS

Whaley Bridge is being evacuated after a 'danger to life' warning was issued over fears a dam could burst.

Toddbrook Reservoir in Whaley Bridge, High Peak, appears to have suffered substantial damage following days of torrential rain.

As a result the Environment Agency issued a severe 'danger to life' flood warning on Thursday afternoon.

The town is now being evacuated.

A spokesman for Derbyshire police said: "Whaley Bridge is being evacuated due to the ongoing situation at Toddbrook Reservoir.

 

[diffident]

How close is the line to the location of the dam??

I've looked on a map briefly, but is it on the other side of a valley? Or is it in direct threat?

 

[175001]

How close is the line to the location of the dam??

I've looked on a map briefly, but is it on the other side of a valley? Or is it in direct threat?

Literally right under it. As is the town!

 

[DarloRich]

very worrying!

 

[sprinterguy]

How close is the line to the location of the dam??

I've looked on a map briefly, but is it on the other side of a valley? Or is it in direct threat?

The railway line is directly below the dam, on the same side of the valley. It's high enough to avoid general flooding of the River Goyt, but if anything happens to the dam then it's in the direct line of fire - As is most of the town.

 

[HOOVER29]

Just seen this on the news.
Makes you wonder what condition the dams are in when you see damage like that.
Do you think it could’ve been caused by the recent very heavy rain.
Last weekend was a corker when it came to the wet stuff.

 

[sprinterguy]

Just seen this on the news.
Makes you wonder what condition the dams are in when you see damage like that.
Do you think it could’ve been caused by the recent very heavy rain.
Last weekend was a corker when it came to the wet stuff.

Based on the video in the article showing the sheer volume of water pouring over the spillway yesterday then I think it can be taken as read that it was caused by the recent heavy rain! Certainly that's what's being reported in the article.

I'm very familiar with this particularly reservoir as the mother of my former partner lives on Reservoir Road (Above the level of the dam, fortunately), and in all the years I went up that way I never saw that sort of volume of water pouring over the spillway - it's usually bone dry.

Lots of issues with the heavy rain locally, with flooding in Bollington, Poynton and Bramhall yesterday. All the talk in the pub last night was of the floods.

 

[Wombat]

Just seen this on the news.
Makes you wonder what condition the dams are in when you see damage like that.
Do you think it could’ve been caused by the recent very heavy rain.
Last weekend was a corker when it came to the wet stuff.

I grew up in Whaley so I've been paying attention to this. Yesterday the dam overflowed due to the very heavy rain, and water was cascading down the concrete face of the dam. This appears to have caused damage to some of that concrete, so the material under the facing has been exposed.

 

[furnessvale]

I grew up in Whaley so I've been paying attention to this. Yesterday the dam overflowed due to the very heavy rain, and water was cascading down the concrete face of the dam. This appears to have caused damage to some of that concrete, so the material under the facing has been exposed.

The water level in the reservoir has now been lowered so none is coming over the spillway. I would think this has greatly reduced the possibility of further erosion of the earth infill of the dam.

 

[Wombat]

The water level in the reservoir has now been lowered so none is coming over the spillway. I would think this has greatly reduced the possibility of further erosion of the earth infill of the dam.

I expect you're right - I certainly hope so! I'm not sure where they're going to drain the water to, in order to fix it. The Goyt has already flooded in various places and while the purpose of the reservoir is to feed the canal, I'd be surprised if the canal has sufficient capacity at the moment.

 

[geoffk]

Can Buxton trains turn back at New Mills or Furness Vale?

 

[furnessvale]

I expect you're right - I certainly hope so! I'm not sure where they're going to drain the water to, in order to fix it. The Goyt has already flooded in various places and while the purpose of the reservoir is to feed the canal, I'd be surprised if the canal has sufficient capacity at the moment.

Indeed! They can put it in the canal but as the spillways into the Goyt are already working overtime no prizes for guessing where all the water ends up!

Meanwhile, further downstream on the Goyt other towns and villages are already flooded.

 

[furnessvale]

Can Buxton trains turn back at New Mills or Furness Vale?

Not at New Mills but they can turn back at Furness Vale, though not when carrying passengers these days.

 

[Wombat]

Indeed! They can put it in the canal but as the spillways into the Goyt are already working overtime no prizes for guessing where all the water ends up!

Meanwhile, further downstream on the Goyt other towns and villages are already flooded.

Hmm, just listening to a chap from the Environment Agency in this video and it seems that they are indeed discharging the water into the Goyt! Possibly the least worst option?

 

[sprinterguy]

Not at New Mills but they can turn back at Furness Vale, though not when carrying passengers these days.

Seems, just for general info, they're cancelling half and turning the others at Hazel Grove at present. Expected to remain that way until the end of Saturday at least.

The water level in the reservoir has now been lowered so none is coming over the spillway. I would think this has greatly reduced the possibility of further erosion of the earth infill of the dam.

That's good news. I sincerely hope for the sake of local residents and business owners that the situation doesn't escalate.

 

[furnessvale]

Hmm, just listening to a chap from the Environment Agency in this video and it seems that they are indeed discharging the water into the Goyt! Possibly the least worst option?

Yes. Increased gradual flooding further downstream would be safer than a catastrophic breach of the dam which would not only ravage Whaley but would still do major sudden damage downstream.

 

[talltim]

You’d think that as the purpose of the spillway was to allow overflow of water it would be able to cope with it. I suspect poor maintenance

 

[furnessvale]

Seems, just for general info, they're cancelling half and turning the others at Hazel Grove at present. Expected to remain that way until the end of the day at least.

Whenever anything goes wrong they always seem to abandon the line above Hazel Grove rather than at least serving as far as New Mills. Turning trains at Furness Vale involves a man using clips and scotches so I suppose that is too much hassle.

 

[furnessvale]

You’d think that as the purpose of the spillway was to allow overflow of water it would be able to cope with it. I suspect poor maintenance

I suspect you suspect wrong.

Film of the overflow yesterday is in the public domain and the volume of water on the spillway was more than any in living memory. The water overtopped the spillway side walls. The water then ran down the grass face of the earth dam, undermining the side wall and the concrete face of the spillway.

 

[swt_passenger]

You’d think that as the purpose of the spillway was to allow overflow of water it would be able to cope with it. I suspect poor maintenance

Indeed much of the reporting seems to be suggesting the “dam collapsed” causing water to overflow. As you say it’s designed to overflow via that concrete paved area, rather than at either side of it which really would quickly damage the structure of the dam. I wonder if the fill beneath the concrete has slumped - which would be out of sight for maintenance purposes.

I saw a documentary a few weeks ago about a major spillway failure in California, and that was because the concrete surface of the spillway was unsupported, and had been installed far too thinly compared to design spec. When the spillway failed water ran out the side of it and started rapidly eroding the earth bank at its side.

(Crossed with above post which provides new info...)

 

[oddiesjack]

I hope somebody is keeping an eye on combs reservoir dam. That's also above Whaley Bridge, also feeds the canal in Whaley, and is (I think) of the same construction. And has received the same amount of rain in the last 7 days.

 

[thejuggler]

I remember a similar situation with Ulley Reservoir dam just outside Rotherham after heavy summer rain.

The danger there was the water would have flooded a major electrical sub station serving most of the town.

 

[darloscott]

Google maps seems to suggest, and backed up by tweets, that New Mills is also now being closed and evacuated. Trains to New Mills Central been stopped and turned at Marple.
The workers on the pathway on top of the dam were working to put sandbags to stop water pouring over the damaged section of the spillway were pulled off rather rapidly. I suspect there is more that we aren't being told going on - my guess is they need to release water rather rapidly into the river.

 

[Greybeard33]

Google maps seems to suggest, and backed up by tweets, that New Mills is also now being closed and evacuated. Trains to New Mills Central been stopped and turned at Marple.
The workers on the pathway on top of the dam were working to put sandbags to stop water pouring over the damaged section of the spillway were pulled off rather rapidly. I suspect there is more that we aren't being told going on - my guess is they need to release water rather rapidly into the river.

According to NRE and Northern JourneyCheck, the closure of New Mills Central is because of flooding between there and Marple, rather than any risk at New Mills itself. The line from Hazel Grove to Chinley is still open.

The piling of sandbags on the top of the spillway suggests that the engineers are not confident that the water can be drained fast enough to prevent it overtopping again. There has been more rain in the catchment this afternoon.

 

[kevconnor]

I remember a similar situation with Ulley Reservoir dam just outside Rotherham after heavy summer rain.

The danger there was the water would have flooded a major electrical sub station serving most of the town.

Ulley Reservoir happened in 2007, problem there was not to dissimilar in that the volume in the reservoir was far too great and started to put pressure on the earthworks which then started to crack. it faced into a valley below which was the town of Catcliffe, said sub-station for the Rotherham area and the M1. I lived in Sheffield at the time and was actually moving out that day it happened as the whole of South Yorkshire was badly affected by the rain that day. by early afternoon most major routes out of Sheffield were flooded and impassable, the don valley, the Wicker and Hillsborough were particularly badly affected. From recollection two people lost their lives that day in south Yorkshire, due to the floods.

 

[Bevan Price]

Yes. Increased gradual flooding further downstream would be safer than a catastrophic breach of the dam which would not only ravage Whaley but would still do major sudden damage downstream.

Yes - on TV News, it said that the reservoir contained millions of tons of water - enough to devastate a large area if the dam collapsed completely.

 

[furnessvale]

Yes - on TV News, it said that the reservoir contained millions of tons of water - enough to devastate a large area if the dam collapsed completely.

Low lying areas of Furness Vale now evacuated

 

[bramling]

Yes - on TV News, it said that the reservoir contained millions of tons of water - enough to devastate a large area if the dam collapsed completely.

Indeed, ISTR something like that happened during the disastrous 1952 Lynmouth flood, albeit on that occasion the dam was formed of debris which eventually gave way under pressure causing a sudden surge. Of course in that situation the danger is not just the water but anything it takes with it becoming a projectile.

Fingers crossed in this case the pressure behind is no longer building up. Thoughts to everyone affected, especially having been in Whaley only a few weeks ago and even visited a couple of dams in the area (although not this one).

 

[Peter Mugridge]

Film of the overflow yesterday is in the public domain and the volume of water on the spillway was more than any in living memory. The water overtopped the spillway side walls. The water then ran down the grass face of the earth dam, undermining the side wall and the concrete face of the spillway.

Images on the news tonight show quite a bit of the earth at the side missing and also clear evidence of missing earth from under the displaced concrete slabs; could it be that the water spilling over eroded the side first and this then allowed the water to get underneath the concrete face of the dam and erode the earth under the slabs leaving those without any support - then they dislodged as a result?

If that is the case, then would not the highest risk be that the earth underneath the slabs, at least at that side, is soaked through and likely to fall away as a result?

 

[nlogax]

Some frightening footage from yesterday's overflow. No wonder so much damage is evident today.